Playable version of canceled Portal prequel F-Stop surfaces after nearly 20 years

Nearly two decades after its cancellation, the camera-based Portal prequel F-Stop is no longer considered lost media, The Verge reported. Leakers have pieced together a playable version of the game using assets from a large 12-terabyte Valve leak earlier this year, along with recently surfaced source code and map data shared on the Valve Cut Content Discord.

F-Stop differs from the mainline Portal games by centering gameplay around a camera mechanic. Players capture items by photographing them and then place those items elsewhere using Polaroid-like photos. This mechanic is somewhat similar to the game Viewfinder, according to The Verge.

The game is short, with full campaign playthrough videos lasting under an hour. This brevity aligns with F-Stop's development context as part of Valve's "Directed Design Experiments," a three-month period in 2007 when the company split into teams to create new game experiments.

Some dialogue and elements from F-Stop were eventually incorporated into Portal 2, but the game itself remained unreleased until this recent leak allowed fans to experience it firsthand.